Helmet cooler



FIG. 1 is a perspective view of a helmet cooler showing our new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a front view thereof; and,

FIG. 6 is a rear view thereof.

The bottom view is planar and unornamented. 

The ornamental design for a helmet cooler, as shown and described. 